Transcript The Database Environment - Eastern Michigan University

Agenda
01/13/05
• Announcement
• Database Development Process
(Chapter 2)
1
Announcement
• A Quiz about Chapter 9 on Tuesday, 01/18/05
– Open book
– Bring your database textbook (or a copy of chapter 9)
to the class
• For your diagramming software, visit the following web
site and download a RFlow trial version:
http://graphicssoft.about.com/cs/diagramswpc
2
Database Development
Process
(Chapter 2)
3
“It is a capital
mistake to theorize
before one has
data”
Sherlock Holms’ remarks in A Scandal in
Bohemia (Sir Conan Doyle, 1891)
4
8 Underlying Principles of
Systems Development
1.
2.
Get the Users Involved
Use a Problem-Solving Approach
3.
Establish Phases and
Activities
4.
Establish Standards for Consistent
Development and Documentation
Justify Systems as Capital Investments
Don’t Be Afraid to Cancel or Revise Scope
5.
6.
7.
8.
Divide and Conquer
Design Systems for Growth and Change
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Strategies for IS Development
Top-Down


Proceeds from general to specific
Particular systems are designed working from a
broad knowledge of the entire organizations
information needs
Bottom-Up


Proceeds from specific to general
Individual systems are designed from a detailed
knowledge of a distinct application
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Information Systems Development Process
Sources


Information systems planning (top-down)
User application requests (bottom-up)
IS Development Approaches


Systems Development Life Cycle (SDLC)
Rapid Application Development (RAD)
- Prototyping
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Information Systems Planning Process
Organization
Mission
Business
Assessment
Organization
Strategic Plan
Current IT Architecture
IS Strategic Plan
New IT Architecture
IS Operational Plan
IS Development Projects
(i.e. Database Development)
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Systems Development Life Cycle
(SDLC)
1. System Identification and Selection
2. Project Initiation and Planning
3. Analysis
4. Logical Design
5. Physical Design
6. Implementation
7. Maintenance
9
System Identification and
Selection
•
•
•
•
•
•
Problem determination
Understanding of the business
situation
Feasibility study
Justification for the system
Authorization to proceed
Priority
10
Project Initiation and Planning
• Scope of the project
•
•
•
•
Project schedule
Resource requirements
Systems architecture
Enterprise data model
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Analysis


System requirements (detailed)
Conceptual model
12
Logical Design

Functional specification of
system components (detailed)
13
Physical Design

Technical specification of
system components (detailed)
14
Implementation

•
•
•
System installation
Applications
Documentation
Training
15
Maintenance
•
•
•
•
System Monitoring
Repairing
Upgrade
Support
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Project Planning
Analysis
Requirements
E-R Data Model
Logical Design
Relational database Model
Qulaity Control Checks
Physical Design
Technical Specifications
Define the database to the
DBMS
Im plem entation
Database SDLC
Data Entry
Information Retrieval
(SQL)
Maintenance
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Database Development Activities in
the SDLC
1.
2.
3.
4.
5.
6.
Planning
Analysis
Logical Design
Physical Design
Implementation
Maintenance
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Planning

Examine the information
systems architecture (blue print)

Review the enterprise data model
•
Establish the general scope of the
database
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Analysis
• Determine the specific data
requirements for the system
• Create the conceptual data model:
Entity-Relationship Diagram
(ERD)
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Basic Entity-Relationship Example
ACCOUNT
Has
EXPENSE
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E-R Diagram Example
Is
Qualified
Prof-ID
Prof-Name
PROFESSOR
COURSE
Course-Num
Course-Title
(4)
Is
Scheduled
Semester
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Logical Design
• Convert the data model to a database
design: Relational Schema
• Perform quality control tuning on the
logical database design
- Integrity constraints
- Normalized relations
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E-R Diagram
ACCOUNT
HAS
EXPENSE
Relations (plus Relational SCHEMA)
ACCOUNT (ACCOUNT_NO, ……)
EXPENSE (EXPENSE_CODE, ACCOUNT_NO)
Plus Constraints, Integrity Rules, Domain……….
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Physical Design

Stipulate technical data
specifications

Define the database design to the
DBMS
•
Construct data entry mechanisms
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Implementation

Load the data

Build the applications
•
Produce documentation
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Maintenance

Tune the database for performance

Provide security and recovery
•
Support the software and files
27
Schema
• The conceptual organization of the
entire database as viewed by
stakeholders
• The structure that contains
descriptions of objects created by a
user such as tables, views and
constraints
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Three Schema Architecture for
Database Development
Conceptual Schema


Analysis phase: E-R Diagram
Logical Design phase: Relational (Logical)
Schema
Internal Schema

Physical Design phase: DBMS Definition
External Schema

Implementation phase: User Views
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Exte rnal Sche m a
Reports
(user V iew )
Forms
(User view )
Programs
(User V iew )
Conce ptual
Sche m a
Three Schema
Database
Architecture
Inte r nal
Sche m a
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Components of Application Logic Involving Data
Input / Output

Manage user input from the keyboard

Format and present output (screens and
hardcopy)
Processing

Data validation

Business rules

Data update

Data and information retrieval
Storage

Performance

Security
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People in Database Development
Systems analysts
Programmers
Database analysts
Database and data administrators
Systems programmers &
network administrators
Technical writers
Users
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To Download RFFLOW Software
Go to
http://graphicssoft.about.com/cs/diagramswpc
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